This invention relates to an explosive rodent trap and in particular to such a trap which does not require pyrotechnic explosives.
Effective control of burrowing rodents, such as moles and gophers, has proven to be a difficult proposition, yet, control of these pests is important due to the wide spread damage they cause whenever large areas of open ground are maintained in a cultivated state. While widely use, poisoned baits and mechanical traps provide sporatic effectiveness at best. Accordingly, attempts have been made to utilize the sensitivity of burrowing rodents to concussive shock as a means of control. Denninger et al., U.S. Pat. No. 4,213,265, Denninger, U.S. Pat. No. 4,109,406, and Sutton, U.S. Pat. No. 2,809,464, all use the detonation of electrically fired pyrotechnic explosive charges, which are placed in a rodent's run, to kill the rodent. While pyrotechnic explosive charges do kill the rodents when fired in their proximity, their use is potentially dangerous since inadvertent firing of a charge before it has been placed in the ground may cause injury to the user. While the danger can be lessened by properly sizing the charge and by careful handling, pyrotechnic explosive charges are inherently dangerous.
Another, perhaps more limiting, shortcoming of prior art explosive rodent traps is that they commonly are fired when the rodent is separated sufficiently from the charge that the explosion will not affect it. This is due to the fact that such devices heretofore have utilized a trigger which is placed in the run itself. Since burrowing rodents typically are pushing dirt before them when they are traveling in their run, this dirt contacts the trigger which then causes the charge to be fired before the mole has reached the charge. Thus the dirt acts as a barrier which prevents the explosive shock from reaching the rodent. Since the amount of dirt which is being cleared by the rodent at any given time varies, it is extremely difficult to adjust for and proper placement of the charge becomes a matter of chance. While this difficulty certainly can be corrected by increasing the strength of the charge, doing so greatly magnifies the chance of injury due to inadvertent firing. Furthermore, if the charge is large enough to ensure that the shock always reaches the rodent it often will cause the run to be blown out entirely scattering dirt onto people and animals standing near it.
What is needed, therefore, is an explosive rodent trap which does not use pyrotechnic explosives and a trigger for an explosive rodent trap which is located outside of the run and which always will be tripped when the rodent is at a particular location in its run.